A process for polymerizing ethylene to obtain an ethylene-based polymer in a plant, wherein the plant includes a reactor in fluid communication with a recycle connection, wherein the process includes a polymerization phase, a partial shutdown phase, and the steps of reducing the pressure in the reactor for entering into the partial shutdown phase from the polymerization phase; and increasing the pressure in the reactor for exiting from the partial shutdown phase and re-entering the polymerization phase.

Generally, an extraction system useful in separating an extract from a matrix using one or more extractants. Specifically, an extractor including one or more of: an extraction vessel having an extractor vessel internal surface which defines an extraction chamber which communicates between open extraction vessel first and second ends, a first piston configured to sealably engage the extractor vessel internal surface of the extraction vessel first end or a second piston adapted to sealably engage the extractor vessel internal surface of the extraction vessel second end.

The invention relates to a pressure vessel, having: a reaction chamber (2) as a pressure space for the initiation and/or facilitation of chemical and/or physical pressure reactions of samples (P) accommodated in the reaction chamber (2); a fluid inlet (20) with a feed valve (21) which is adjustable between an open position, for the feed of a fluid, preferably a flushing gas, into the reaction chamber (2), and a closed position, for stopping the feed of the fluid; a fluid outlet (30) with a discharge valve (31), which is adjustable between an open position, for the discharge of a fluid out of the reaction chamber (2), and a closed position, for stopping the discharge of the fluid out of the reaction chamber (2); and an oxygen sensor (33) for detecting an oxygen content in the reaction chamber (2). The pressure vessel (1) furthermore has a control device which is configured to control the feed valve (21) and the discharge valve (31) on the basis of the oxygen content detected by the oxygen sensor (33), such that the reaction chamber (2) is flushed via the feed and discharge valves (21, 31) situated in the open position, and at least the discharge valve (31) switches from the open position into the closed position as soon as a predetermined oxygen content is undershot. The invention also relates to a corresponding method.

The present invention relates to a pressure vessel (1) for receiving samples (P) to be heated, having a reaction chamber (2) as a pressure space for the initiation and/or facilitation of chemical and/or physical pressure reactions, the reaction chamber (2) being designed for receiving a liquid (5), a magnetic disk (8) mounted rotatably about an axis of rotation in the reaction chamber (2), and a magnet arrangement (10), provided outside the reaction chamber (2), for generating a rotating magnetic field for rotationally driving the magnetic disk (8) about its axis of rotation, the magnetic disk (8) having at least one passage bore (13), which extends transversely in relation to the axis of rotation and is provided in such a way that liquid (5) received in the reaction chamber (2) is driven through the passage opening (13) by rotation of the magnetic disk (8) in order to stir the liquid (5).

The present invention relates to a pressure vessel (1) having a pressure vessel wall (1a) which completely surrounds a reaction chamber (2) as a pressure space for the initiation and/or promotion of chemical and/or physical pressure reactions of a sample (P) to be heated which is accommodated in the reaction chamber (2), wherein the pressure vessel wall (1a) has an infrared-permeable high-pressure window (30) which extends away outward in a direction from the reaction chamber (2) and which is supported in the pressure vessel wall (1a) with respect to a pressure in the reaction chamber (2), wherein the pressure vessel (1) furthermore has an infrared to temperature sensor (40) which is situated directly opposite the high-pressure window (30), in order to measure the temperature of a sample (P), accommodated in the reaction chamber (2), during a pressure reaction through the high-pressure window (30).

A cap closes a sample vessel for the microwave treatment of samples. The cap contains a closure body for closing the sample vessel. The closure body is fitted to the sample vessel and closes the sample vessel at a sealing surface. A spring-loaded pressure relief valve and a vent duct are provided. The vent duct, the pressure relief valve and the closure body are configured in such a manner that the vent duct connects the closure body via the pressure relief valve to the surrounding area such that when a defined first pressure level is exceeded at the closure body excess pressure can escape through the vent duct into the area surrounding the cap. A reservoir is provided. The reservoir and the vent duct are configured such that condensate precipitating in the vent duct accumulates in the reservoir when the cap is in the state fitted to the sample vessel.

A reactor for performing a gas/liquid biphasic high-pressure reaction with a foaming medium, comprising an interior formed by a cylindrical, vertically oriented elongate shell, a bottom and a cap, wherein the interior is divided by internals into a backmixed zone and a zone of limited backmixing, wherein the backmixed zone and the zone of limited backmixing are consecutively traversable by the reaction mixture, wherein the backmixed zone comprises means for introducing gas and liquid and a gas outlet and also comprises at least one mixing apparatus selected from a stirrer, a jet nozzle and means for injecting the gas, and the zone of limited backmixing comprises a reaction product outlet, a first cylindrical internal element which in the interior extends in the longitudinal direction of the reactor and which delimits the zone of limited backmixing from the backmixed zone, backmixing-preventing second internal elements in the form of random packings, structured packings or liquid-permeable trays arranged in the zone of limited backmixing and a riser tube whose lower end is arranged within the backmixed zone and whose upper end opens into the zone of limited backmixing so that liquid from the backmixed zone can ascend into the zone of limited backmixing via the riser tube, wherein flow into the zone of limited backmixing enters from below. The reactor is configured such that the high-pressure reaction space is optimally utilized and contamination of workup steps or subsequent reactions arranged downstream of the high-pressure reaction with foam is substantially avoided. The invention further relates to a process for performing a continuous gas/liquid biphasic high-pressure reaction in the reactor.

A pulsed compression reactor may include a reactor housing, a spring piston, and a driver piston. The reactor housing may define an interior volume, and may include a first passage and a second passage which lead to the interior volume. The spring piston may be positioned within the interior volume, wherein the spring piston and the reactor housing at least partially define a perimeter of a gas spring buffer chamber within the interior volume. The driver piston may be positioned within the interior volume, wherein the spring piston, the driver piston, and the reactor housing at least partially define a perimeter of a reaction chamber within the interior volume.

Provided is a highly practical pressure vessel in which there is minimal inside diameter deformation even if openings in a center inlet/outlet part are large, and there is little pressure-induced elongation from a center to both ends. This pressure vessel is composed of a tube body made of a fiber-reinforced resin, wherein: a center inlet/outlet part that lets a liquid in or out is provided to a tube-body-axial center part on a peripheral surface of the tube body; end-part inlet/outlet parts that let a fluid in or out are provided to tube-body-axial end parts of the tube body; the tube body is configured from a helical layer of which fibers are inclined at an angle of from 40 to less than 50 relative to a tube-body-axial direction, a reinforcing layer of which fibers are inclined at a greater angle than the helical layer relative to the tube-body-axial direction, and a seal layer constituting an innermost layer; a breakaway part that breaks away circumferentially outward from the seal layer is provided to a position on the helical layer where the center inlet/outlet part is provided; the reinforcing layer is configured from an inward reinforcing layer and an outward reinforcing layer provided respectively to inward and outward sides of the helical layer so as to enclose the breakaway part of the helical layer therebetween; and the center inlet/outlet part is provided so as to penetrate the inward reinforcing layer, the breakaway part of the helical layer, and the outward reinforcing layer.

Disclosed is a combined reformer including two or more catalyst tubes reacting at different temperatures, having different reforming reactions continuously performed as a combustion gas sequentially supplies heat to two or more catalyst tubes, and capable of easily replacing a catalyst, and a catalyst replacement method thereof.